O-(alpha-hydroxyalkyl)phenyl n-methyl carbamates

ABSTRACT

O-(A-HYDROXYALKYL)PHENYL N-METHYL CARBAMATES OF THE FORMULA   1-(CH3-NH-COO-),2-(R-C(-R1)(-OH)-)BENZENE   WHEREIN R IS HYDROGEN OR METHYL AND R1 IS ETHYL OR PROPYL, WITH THE PROVISO THAT THE TOTAL NUMBER OF CARBON ATOMS FOR R AND R1 TAKEN TOGETHER IS 3. THE ABOVE CARBAMATES FIND USE AS INSECTICIDES.

Patented Jan. 16, 1973 Compounds of the present invention are prepared by 3,711,536 reacting an appropriate phenol with methyl isocyanate d gggg N'METHYL according to the following equation: Gustav K. Kohn, Berkeley, Calif., assignor to Chevron Research Company, San Francisco, Calif. 5 JL No Drawing. Filed Mar. 24, 1971, Ser. No. 127,779 0H 7 The portion of the term of the patent subsequent to ?i%i"t1f?5i% K K n c r US. Cl. 260-479 c 3 Claims 10 CHQNCO l R1 OH H (1) ABSTRACT OF THE DISCLOSURE GeneraIIy equimoIar amounts of the phenol and the -(a-Hydroxyalkybphenyl N-methyl carbamate's of th isocyanate will be used. The amount of the isocyanate f rm la should not exceed about 1.1 moles per mole of phenol. 0 Generally, a small amount of triethylamine or other suita able organic base is added. The reaction is generally run NHCHI in the presence of a solvent such as dimethoxy or methylvene chloride. The amount of solvent will range from 2 moles to 20 moles per mole of phenol. The reaction temhe R1 perature will range from 20 C. to 85 C. and the reaction time /2 to 72 hours.

The phenol of reaction (I) above can be obtained comgi g R h fi i g z g andbRl 1S g i mercially or it can be prepared by the well-known reac- R tartar. that g utamate: of a. or find use as hisecficidesg e benzaldehyde with an appropriate Grignard reagent. The

Grignard reagent may be, e.g., ethyl magnesium bromide orpropyl magnesium bromide. The reaction is generally run at a temperature of from 0 C. to 10 C. Generally, BACKGROUND OF THE INVENTION magnesium turnings will be mechanically stirred with the Field appropriate hydrocarbyl bromide to form the Grignard reagent; then the ketone added. The product can be recovered by the addition of water and extracted with ether. If desired, the o-hydroxyphenyl methyl ketone or o-hy- 'droxybenzaldehyde can be prepared by the well-known H I reaction of acid halide with phenol in the presence of Prior art 1 I I aluminum trichloride, etc. m A1ky1pheny1 N methy1 carbamates are n known The present invention may be more fully understood in the art as agricultural pesticides, particularly for their b the followmg examples: effectiveness as digestive and/or contact toxicants which EXAMPLE 1 inhibit the cholinesterase enzyme system of the parasite.

The present invention relates to insecticidal carbamates. More particularly, the present invention is concerned with o-a-hydroxyalkylphenyl N-methyl carbamates and. their use in the control of insects. I

See for example US. Pat. Nos. 3,062,707; 3,062,864; Preparation of o-(2-hydroxy-2-butyl)phenyl 3,062,865; 3,062,866; 3,062,867; 3,062,868; 3,066,163; N-methyl carbamate 7 d 3076741 an 3 110 726 To a vigorously stirred solution of 10 g. (0.412 mole) DESCRIPTION THE INVENTION of magnesium turnings in 250 ml. of diethyl ether there Carbamates of the present invention find use in pestiwas added a Small g g of a of 45 cide control and are represented by the f l 'mole) of ethylbromlde in 100 ml. of diethyl ether. After a short time, a crystal of iodine was added, and then the O remainder of the ethylbromide solution was added over a o- -NHoH, period of one hour. During this time the reactants were maintained at a gentle reflux temperature. When all of the C-R bromide solution was added, the mixture Was stirred at room temperature for M2 hour.

A solution of 27 g. (0.2 mole) of o hydroxyacetophenone dissolved in 200 ml. of diethyl ether was then added wherein R is hydrogen or methyl and R is ethyl or propyl over a period of 1 hour, and then the desulting mixture (nor iso), with the proviso that the total number of was stirred at room temperature for an additional hour. At carbon atoms for R and R taken together is 3, i.e. that the end of this time. the mixture was cooled t0 0' 0-, when R is propyl, R is hydrogen. and 250 ml. of saturated aqueous ammonium chloride was Representative compounds of the present invention are slowly added. After filtration, the phases were separated o-(l-hydroxypropyDphenyl N-methyl carbamate, o-( 1- and the dried organic layer was evaporated to give a crude hydroxybutyl)phenyl N-methyl carbamate, o-(l-hydroxyliquid product. This material was chromatographed on 2-methy1)phenyl N-methyl carbamate, o.-(2-hydroxy-2- silica gel using first a 95/5 and then a 50/50 hexane/dibuty1)phenyl N-methyl carbamate. ethyl ether solution as the eluant. The fractions containing g. of o-(2-hydroxy-2-butyl)phenol.

The phenolic product obtained as above, g.. (0.072 I mole) was dissolved in 50 ml. of dimethoxyethane to which was added 4.12 g. (0.072 mole) of methyl isocyamate and 2 ml. of triethylamine. The resulting solution was refluxed for 40 hours. At the end of this time the solvent was removed by evaporation and replaced by an equal amount of dichloromethane. After washing and drying the solvent was evaporated off to give an oily crude product. Purification by chromatography over silica gel using ether-hexane solution as the eluant gave 16 g.of o-(2- hydroxy-2-butyl)phenyl N-methyl carbamate.

Analylsis.-Calcd. for C12H1'1NO3: N, 6.3%. Found: N, 5.8%. The infrared spectra had strong adsorption bands at 760, 920, 1100, 1200, 1340, 1440, 1480, 1530, 1700, 2980, and 3300 cm.- The NMR spectra was consistent with the assigned structure.

Other compounds were made by essentially the same procedure starting with either o-hydroxybenzaldehyde or o-hydroxyacetophenone. These compounds are listed in Table I.

TABLE I Analysis, percent N Physical Compound state Calculated Found 0-(1-hydroxy-2-rnethylpropyl)- on 6.3 6.4

phenyl N-methyl carbamate. o-(l-hydroxypropyDphenyl N- do 6. 7 6. 9

methyl carbamate.

In addition to the specific formulations and application techniques described below, one or more of the carbamates of the present invention may be applied in other liquid or solid formulation to the insects, their environment, or hosts susceptible to insect attack. For example, they may be sprayed or otherwise applied directly to plants or soil so as to effect control of insects coming into contact therewith.

Formulations of the compounds of this invention will comprise a toxic amount of one or more carbamates and a biologically inert carrier. Usually they will also contain a wetting agent. Solid carriers such as clay, talc, sawdust and the like may be used in such formulations. Liquid diluents which may be used with these compounds include water and aromatic solvents. In addition theseformulations may contain other compatible pesticides, fillers, stabilizers, attractants and the like.

The concentration of the active ingredient tobe-used with inert carriers, eiher solid or liquid carriers, .will be dependent upon many factors, such as the particular carbamate compound which is used, the carrier in or upon which it is incorporated, the method and conditions of application, the insect species to be controlled, etc., the proper consideration of these factors being within the skill of those versed in the art. In general, the toxicingredients of this invention will be eflective in concentrations from about 0.0001 percent by weight to as high as 50 percent by weight or higher. Economically, of course, it is desirable to use lower concentrations of this active ingredient. Thus,

it-is usually desirable to use less than 2-0 percent by weight of the active ingredient in a particular composition.

The terms insecticide and insect as used herein refer to their broad and commonly understood usage rather than to those creatures which in the strict biological sense are classified as insects. Thus, the term insect is used not only to include small invertebrate animals belonging to the class Insecta but also to other related classes of arthropods whose members are segmented invertebrates having more or fewer than six legs, such as spiders, mites, ticks, centipedes, worms and the like.

To show the insecticidal activity of the compounds of the present invention, two representative compounds were tested in their control of American cockroaches (Preiplaneta americana L.)

For the insecticidal test, 500 p.p.m. acetone solution of the candidate toxicant was placed in a microsprayer (atomizer). A random mixture of anesthetized male and female roaches was placed in a container and 55 mg. of the above-described acetone solution was sprayed on them. A lid was placed on the container. A mortality reading was made after.24 hours. The test results showed that for o-(2-hydroxy-2-butyl)phenyl N-methyl carbamate the control was For the other candidate toxicant, namely 0 (1 hydroxy-2-methylpropyDphenyl N-methyl carbamate, the control was 98%.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. Compound .of the formula 3,470,236 9/1969 Hausweiler Bl. al 260-479 JAMES A. PATTEN, Primary Examiner I US. Cl. X.R. 424-30Q 

